Hydraulic fluids containing nonionic surface action agents and phosphate esters of nonionic surface active agents



United States Patent HYDRAULIC FLUIDS CONTAINING NONIONIC SURFACE ACTIONAGENTS AND PHOSPHATE ESTERS 0F NONIONIC SURFACE ACTIVE AGENTS JealSugarman, Flushing, N.Y., and Fred E. Woodward,

Watchung, N.J., assignors to GAF Corporation, a corporation of DelawareNo Drawing. Filed Feb. 10, 1967, Ser. No. 615,063

Int. Cl. C09k 3/00, 3/02 US. Cl. 252-75 6 Claims ABSTRACT OF THEDISCLOSURE A water-in-oil emulsion hydraulic fluid comprising about a 20to 60% by weight water phase and about a 40 to 80% by weight oil phase,wherein said emulsion also contains (I) about 0.5 to 10% by weight basedon the weight of the oil, of a mixture of monoand diphosphate esters andsalts thereof and (II) about 0.5 to 10% by weight based on the weight ofthe oil, of a polyoxyethylene ether of an aliphatic alcohol surfaceactive agent.

BACKGROUND OF THE INVENTION This invention relates to new and usefulinvert (waterin-oil) emulsions and more particularly to invert mineraloil emulsions which are outstanding lubricating and hydraulic fluids.This invention is especially concerned with fire resistant hydraulicfluids which have outstanding lubricity and stability characteristics.

The conventional hydraulic fluid is a petroleum oil which is anexcellent fluid for this function when properly formulated with suitablecorrosion inhibitors, antioxidants, extreme pressure additives, etc.,but it suffers from the one major deficiency of flammability. Recently,considerable efforts have been directed toward the development ofhydraulic fluids to replace such oils by developing fluids which retainthe beneficial properties of the oil, but which would be essentiallyfire resistant and have good stability. An acceptable hydraulic fluidshould have the following characteristics:

(1) Optimum hydraulic efliciency (2) Excellent lubrication (3) Corrosionprotection (4) No effect on seals in hydraulic systems (5) Stability (6)Low flammability (7) Low cost Properly formulated petroleum oils areexcellent hydraulic fluids, however, they have the distinct drawback ofbeing etxremely flammable. Serious fires have been caused by hydrauliclines rupturing and the subsequent release, under high pressure, of theoil onto molten metal in die casting operations or the oil coming intocontact with heated parts or sparks from electrical equipment, causingignition of the oil. This serious hazard has led industry 'to initiateprograms in changing over to fire resistant hydraulic fluidsparticularly in coal mines as well as in various other obviousindustrial applications.

Three types of fire resistant hydraulic fluids have been reported. Theyare:

(1) Straight synthetic liquids of the organic phosphate ester type(e.g., tricresyl phosphate).

(2) Water-glycol fluids generally based on polyethylene glycols.

(3) Water-in-oil (invert) emulsions.

While the first two types normally exhibit good lubricity and wearproperties, they are quite expensive and vary in their fire resistantand stability properties. The

3,532,632 Patented Oct. 6, 1970 third type has opened up a new horizonin this field. The use of water-in-oil (invert) emulsions allows the oilto remain in a continuous phase so that the hydraulic fluid may retainand exhibit the beneficial anti-corrosion and lubricating properties ofthe oil while also being resistant to flammability as well. However,merely emulsifying a petroleum oil with water fails to yield an emulsionof adequate lubricating qualities or stability, especially at highpressures.

It has now been discovered that stable, water-in-oil emulsions can beprepared having outstanding fire-resistaht, lubricity and wearproperties by the employment of the instant invention.

It is therefore an object of the present invention to provide new anduseful water-in-oil emulsions. It is another object of this invention toprovide new and useful water-in-oil emulsions which are outstandinghydraulic fluids. It is still another object of the present invention toprovide new and useful water-in-oil emulsions which have outstandinglubricating characteristics. It is a further object of this invention toprovide new and useful water-in-oil emulsions which are stable and fireresistant under heat and pressure. Other objects, advantages andapplications of the instant new and unobvious water-in-oil emulsions ofthe instant invention will be readily apparent from the followingdetailed description as well as the appended claims.

SUMMARY OF THE INVENTION The disadvantages of the prior art are overcomeand the forementioned as well as other objects of the instant inventionare accomplished according to the present invention by providingWater-in-oil emulsions which comprise from about 20-60% by weight waterand from about 40-80% by weight oil, to which has been added (I) fromabout 0.5% to about 10% by weight based on the weight of the oil, of amixture of phosphate esters and salts thereof of a nonionic surfaceactive agent hereinafter to be described and (II) about 0.5 to about 10%by weight based on the weight of the oil, of a nonionic surface activeagent derived from an aliphatic alcohol also to be further described.

The mixture of phosphate esters of nonionic surface active agents whichis herein contemplated is a mixture of oil-soluble or oil-dispersiblemonoand diphosphate esters and salts thereof. The nonionic precursorsfor said esters are selected from the group consisting ofpolyoxyalkylene ethers of alkyl phenols and aliphatic alcohols rangingfrom at least 8 carbon atoms to about 70 carbon atoms, derived bycondensing the alcohols with an alkylene oxide such as ethylene oxide,propylene oxide or butylene oxide or mixtures thereof. Thus, saidoxyalkylene groups may contain from 2 to 4 carbon atoms each. The amountof oxyalkylene groups may vary from about 10% (i.e., derived from theinteraction of 1 mole alkylene oxide) up to about 47 weight percent toweight percent (depending upon the oxyalkyl groups) based upon theweight of the nonionic. For example, the maximum weight percent ofoxyalkylene when ethylene oxide is utilized is about 47 weight percent,while it is about 60 weight percent for propylene oxide and about 75weight percent for butylene oxide. The ratio of mono phosphate ester todiphosphate ester in the above mentioned mixture is not critical, sinceany mixture amounting from about 0.5% to about 10% by weight based onthe weight of the oil may be used.

The nonionic surface active agent derived from an aliphatic alcohol,which is present in the water-in-oil emulsion in addition to thephosphate esters, acts as an auxiliary emulsifier. It has beensurprisingly discovered that the presence of this additional surfactantcontributes the unobvious effect of making the water-in-oil emulsionvery stable.

The nonionic surface active agent which is to be used in combinationwith the above described phosphate esters is extremely critical inobtaining a satisfactory, stable, invert emulsion. The nonionic surfaceactive agent must be one which is dervied from an aliphatic alcohol of Cto C condensed with from about 1.0 to about 3 moles of ethylene oxide,and preferably 1.5 to 2.5. Suitable alcohols include dodecyl alcohol,tridecyl alcohol, tetradecyl alcohol, pentadecyl alcohol, hexadecylalcohol, stearyl alcohol, oleyl alcohol, primary-m-eicosyl alcohol,tricosyl alcohol, and n-tetracosyl alcohol. In addition to suchalcohols, various naturally occurring mixtures which predominate inthese alcohols may be used such as the mixed coco alcohols, tallowalcohol and the like.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The nonionic oxyalkylatedproducts which are herein contemplated as precursors for the phosphateesters are well known in the art and are derived by reacting alkylphenols or aliphatic alcohols of at least 8 carbon atoms with alkyleneoxide as, for example, disclosed in US. Pats. 2,213,477 and 1,970,578.The preferred alkyl phenols are those having an alkyl or a plurality ofalkyl substituents having a total of at least 8 carbon atoms in thealkyl chain or chains. The preferred aliphatic alcohols are those havingabove about 12 carbon atoms in the molecule. The following illustratesome typical suitable phenols and alcohols which may be used to form thecorresponding nonionic surface active agents which are precursors forthe instantly contemplated phosphate esters:

octyl phenol (diisobutylene) nonyl phenol (nonyl derived from propylenetrimer) dodecyl phenol (derived from propylene tetramer) dibutyl phenoldiamyl phenol hexadecyl phenol octadecyl phenol, and the like phenolscontaining a plurality of different alkyl groups, for example:

butyl amyl phenol butyl hexyl phenol amyl hexyl phenol amyl heptylphenol ethyl heptyl phenol as well as phenols containing a plurality ofsimilar alkyls such as, in addition to those above:

di-n-hexyl phenol diisohexyl phenol di-n-heptyl phenol di-n-octyl phenoldiiso-octyl phenol dinonyl phenol didodecyl phenol ditetradecyl phenoldiocta decyl phenol tri-n-octyl phenol trioctadecyl phenol tri-n-butylphenol, and the like, as well as n-octyl alcohol iso-octyl alcoholn-nonyl alcohol n-decyl alcohol undecyl alcohol lauryl alcohol tridecyl(oxo) alcohol tetradecyl alcohol pentadecyl alcohol hexadecyl alcoholstearyl alcohol oleyl alcohol mixed coco alcohols hydrogenated tallowalcohol ROH alcohols prepared from olefins of C to C by the 0x0 process,i.e., addition of H C=O and hydrogenation to the alcohol: benzylalcohol, substituted benzyl alcohols,

where R is C to C $113 RfiNHCHGHzOH where R is C, to C CHzCHzOH where Ris C to C and the like.

The above compounds may be easily reacted with the alkylene oxide asdescribed above to yield the nonionic surface active agents which arethen used to prepare phosphate esters employed in the compositions ofthe present invention.

In addition to the oxyalkylated derivatives of the afore mentionedcompounds, other oxyalkylated derivatives that may be employed, ifdesired, are the oxyalkylated derivatives of thio-alcohols, amides,sulfonamides and the like which have a reactive hydrogen atom capable ofreacting with an alkylene oxide to yield an hydroxy compound which, likethe compounds listed above, can also be phosphated.

One of the methods for preparing suitable phosphate esters employed inthe instant invention, involves the reaction of 1 mole of P 0 with 2 to4.5 moles of the nonionic surfactant as described and claimed in US.Pat. 3,004,056 by Nunn and Hesse and US. Pat. 3,004,057 by Nunn. Asdescribed in said Nunn and Hesse patent, the reaction between the P 0and the nonionic polyoxyalkylene ether is conducted under substantiallyanhydrous conditions and at a temperature below about C. In itspreferred form, the reaction is carried out by adding the P 0 gradually,with vigorous agitation to the nonionic surface active agent in liquidform. The reaction is exothermic and cooling is in some cases necessaryto keep the temperature below 110 C., since discolored and darkenedproducts tend to be produced above this temperature. The reactionproceeds continuously during the addition of the P 0 and is preferablyfollowed by maintenance of the reaction mixture at ambient temperaturesup to 110 C. for an additional period of time after completion of suchaddition to allow for complete solution of the P 0 and reaction with thenonionic surface active agent.

By carrying out the above reaction in the presence of a small amount ofa phosphorous-containing compound, selected from the group consisting ofhypophosphorous acid, salts of hypophosphorous acid, phosphorous acid,and salts and esters of phosphorous acid, preferably sodiumhypophosphite or hypophosphorous acid, as described in said Nunn '057patent, lighter colored or substantially colorless reaction products areobtained.

Monoesters and diesters can also be prepared from the correspondingtriesters by reacting the triester with phosphoric acid. By varying theratio of nonionic to acid, one can prepare either monoor diester to thesubstantial exclusion of the other. A high ratio of triester to acid(2:1) produces diester, whereas a low ratio (0.5 :1) produces monoester.It is also obvious that the mixture of phosphate esters may be readilyprepared by merely combining one or more monophosphate esters with oneor more diphosphate esters.

Thus, the monoand di-phosphated products may be represented by thefollowing formulas:

R CHCHzO -OI OX (3 t. and

wherein R represents H, or methyl; X may be hydrogen, alkali metal,alkaline earth metal, e.g., calcium, magnesium, barium, etc., ammoniumor substituted ammonium, and n equals the number of moles of alkyleneoxide necessary to yield a final product containing up to 75% by weightof the said alkylene oxide as discussed above; R is the alcohol orphenol hydrophobe nucleus.

The following examples are illustrative of the present invention and arenot to be regarded as limitative. It is to be understood that all parts,percentages and proportions referred to herein and in the appendedclaims are by weight unless otherwise indicated.

Example I A mixture of monoand di-phosphate esters are prepared byreacting 2.7 moles of a nonionic surface active compound derived fromdinonyl phenol condensed with 7 moles of ethylene oxide with 1 mole of P0 in the manner described in the examples of US. Pat. 3,004,056.

In general, procedures for preparing the subject emulsions involvedissolving the selected phosphate ester and the nonionic surface activeagent in the selected oil and thereafter adding water slowly withsufficient stirring, whereby a water-in-oil emulsion is formed.

Example II (A) Preparation of phosphate ester barium salt: 50 g. of thephosphate ester of Example I above are dissolved in 50 g. of Esso Base FOil which is a non-solvent refined neutral oil with a KB value=l9.l.17.0 g. of barium hydroxide-H O are then added and the mixture isstirred until uniform. The resulting product is an opaque viscousliquid, the pH of a 1% solution of which in distilled water is 9.3.

(B) Preparation of water-imoil emulsion: To 53.1 g. of Esso Base Oil Fthere are added 5.9 g. of the liquid prepared in Part A above and 1 g.of the nonionic surfacant derived from the condensation of oleyl alcoholwith 3 moles of ethylene oxide. The mixture is stirred until a uniformproduct is obtained. 40 g. of water are then slowly added with highspeed propeller stirring. An especially smooth, stable, non-flammable,white water-inoil emulsion is formed.

After standing 14 days at 90 C., two thirds of the emulsion separatedinto a clear oil phase on top with one third of the emulsion remainingintact. However, on shaking, the water-in-oil emulsion was easilyre-fonmed. No water separation was ever noted. This demonstrates thatunder the constant agitation of a pump, the water-in-oil emulsion, whenin actual use, will remain very stable and completely intact.

Example III Example II is repeated except that the nonionic surfactantemployed in Part B is a condensation product of tallow alcohol plus 2moles of ethylene oxide which yields like results.

Example IV (A) The procedure of Example I is repeated using dodecylphenol which has been condensed with 7 moles of ethylene oxide.

(B) To 51 parts of Solvent-Refined Midcontinent Oil (150 SUS, neutral)there are added 1.5 parts of the phosphate ester of Part A above and 4.0parts of the nonionic surfactant described in Example III.

(C) To 43 parts of water there are added 0.5 part of barium hydroxide .8H O.

(D) The aqueous solution of Part C is then slowly added to the oilprepared in Part A with stirring. An outstanding stable, non-flammable,water-in-oil emulsion is produced.

Example V (A) Example I is again repeated except that the nonionicemployed is derived from nonyl phenol condensed with 1.8 moles ofethylene oxide.

(B) To 54 parts of the oil described in Example IVB there are added 2parts of the phosphate ester of Part A above and 1 part of the nonionicalso described in Example IVB.

(C) To 43 parts of water there are added .24 part of calcium hydroxide.

(D) Parts B and C are mixed as in Example IV to produce an excellentstable, non-flammable, water-in-oil emulsion.

Example VI Example V is repeated except that 53 parts of oil are used inPart B and 2 parts of the nonionic are employed instead of 1 part whichyields like results.

Like results may also be obtained by replacing the above employedphosphate esters with mixtures of mono and diphosphate esters derivedfrom the following polyoxyalkylene compounds:

dinonyl phenol+4 moles ethylene oxide dodecyl phenol+2 moles ethyleneoxide dinonyl phenol-l-S moles ethylene oxide dinonyl phenol+1.5 molesethylene oxide dodecyl phenol+1.8 moles ethylene oxide octadecanol+2moles ethylene oxide hexadecanol+4 moles ethylene oxide l-eicosanol+6moles ethylene oxide l-dotriacontanol-l-7 moles ethylene oxide dodecylphenol-I-S moles ethylene oxide hexadecyl phenol+3 moles ethylene oxidetri-n-octyl phenol+ r moles ethylene oxide tri-n-octyl phenol+5 molespropylene oxide dodecyl phenol+3 moles propylene oxide dinonylphenol+1.5 moles propylene oxide diisohexyl phenol+2 moles propyleneoxide tri-n-butyl phenol+2 moles propylene oxide tri-n-butyl phenol+3moles propylene oxide trim-butyl phenol+2 moles ethylene oxide+2 molespropylene oxide tri-n-butyl phenol+3 moles ethylene oxide hexadecanol+3moles propylene oxide octadecanol+4 moles propylene oxide butyl hexylphenol+4 moles ethylene oxide ethyl heptyl phenol+5 moles ethylene oxideethyl heptyl phenol+3 moles propylene oxide ceryl alcohol+2 molesethylene oxide 1-ocracosanol-i-4 moles ethylene oxide 1-nonacosanol+7moles ethylene oxide 1-triacontanol+6 moles ethylene oxidel-tetratriacontanol-l-S moles ethylene oxide l-tetratriacontanol-i-Zmoles propylene oxide and the like. Moreover, similar results may alsobe obtained by replacing the above employed nonionic surfactants withother aliphatic surfactants, such as,

dodecyl alcohol+2 moles ethylene oxide tetradecyl alcohol+3 molesethylene oxide hexadecyl alcohol+1.5 moles ethylene oxide stearylalcohol+l.5 moles ethylene oxide primary-m-eicosyl alcohol+l moleethylene oxide n-tetracosyl alcohol+2.5 moles ethylene oxide and thelike.

7 Example VII In order to demonstrate the wear and corrosion resistantproperties of the instant water-in-oil emulsions, the followingcomparative test was carried out:

The amount of wear in a Vickers Vane type pump (Model V-104C, 8gallons/minute delivery) was determined utilizing the Water-in-oilemulsion product of Example II as compared to the amount of wearutilizing a commercially available product, Iris 902 (Shell Oil Co.).The following data illustrates the wear properties of each fluid:

Water-in-oil emulsion of Example II:

Duration-267 hours Temperature6065 C. Pressure450500 p.s.i.

Rate of cam ring wear-2.61 mg./hr. Rate of vane wear0.303 mg./ hr.

Iris 902:

Durationl hours Temperature4550 C. Pressure450500 p.s.i.

Rate of cam ring wear5.1l mg./hr. Rate of vane wear0.415 mg./hr.

After the above test, the cam ring and vane of the experimental runutilizing the water-in-oil emulsion of Example II was found, upon visualinspection, to be clean and free from corrosion, pitting, etc.

Various modifications and variations of this invention will be obviousto a worker skilled in the art and it is understood that suchmodifications and variations are to be included within the purview ofthis application and the spirit and scope of the appended claims.

We claim:

1. A water-in-oil emulsion hydraulic fluid consisting essentially offrom about a to about a 60% water phase and from about a 40% to about an80% oil phase and to which has been added (I) from about 0.5% to about10% by weight based on the weight of the oil, of a mixture of mono anddiphosphate esters and salts thereof of the formulae wherein Alkrepresents an alkylene group selected from the group consisting ofethylene, propylene, and butylene,

R represents the residue of an alkyl phenol or aliphatic alcohol from 8to about carbon atoms, X is selected from hydrogen, alkali metals,alkaline earth metals, ammonium or substituted ammonium, and n equalsthe number of moles of alkylene oxide such that the nonionic precursorof said mixture of monoand diphosphate esters and salts thereof containsa maximum of about 47 weight percent of ethylene oxide, a maximum ofabout 60 weight percent of propylene oxide and a maximum of about weightpercent of butylene oxide depending upon the alkylene oxide used, and(II) from about 0.5% to about 10% by weight based on the weight of theoil of a nonionic surface active agent derived from the condensation ofan aliphatic alcohol of from 12 to 24 carbon atoms with from about 1.5to about 3.0 moles of ethylene oxide per mole of alcohol.

2. A water-in-oil emulsion hydraulic fluid as defined in claim 1,wherein ingredient (II), the nonionic surface active agent, derived froman aliphatic alcohol and ethylene oxide, is the condensation product ofoleyl alcohol and 3 moles of ethylene oxide.

3. A water-in-oil emulsion hydraulic fluid as defined in claim 1,wherein ingredient (II), the nonionic surface active agent, derived froman aliphatic alcohol and ethylene oxide is the condensation product oftallow alcohol and 2 moles of ethylene oxide.

4. The water-in-oil emulsion hydraulic fluid of claim 1 wherein R is theresidue of dinonyl phenol, Alk is ethylene, and X is barium.

5. The water-in-oil emulsion hydraulic fluid of claim 1 wherein R is theresidue of dodecyl phenol, Alk is ethylene, and X is barium.

6. The water-in-oil emulsion hydraulic fluid of claim 1 wherein R is theresidue of nonyl phenol, Alk is ethylene, and X is calcium.

References Cited UNITED STATES PATENTS 2,965,574 12/1960 Tierney et al252-78 3,269,946 8/1966 Wiese 25278 X 3,311,561 3/1967 Anderson et al252-78 X 3,004,056 10/1961 Nunn 260950 3,010,903 11/1961 Clarke et al.260980 3,278,442 10/1966 Beerbower et al. 252-75 3,331,896 7/1967Eiseman et al 260980 HERBERT B. GUYNN, Primary Examiner M. HALPERN,Assistant Examiner U.S. Cl. X.R. 25278, 498

